1. Field of the Invention
This invention generally relates to key management for cryptographic data processing.
2. Background Art
Encryption of data prevents access to the data by unauthorized entities. Sensitive data such as bank account numbers, credit card numbers, social security identification, home address and phone numbers is increasingly being stored on computer systems and transported across networks. One technique to secure this information from unauthorized disclosure is encrypting the data prior to storage and/or transport.
Data is encrypted using an encryption key. Often these keys are stored in the clear (i.e. in their “plaintext” form). These unencrypted keys are referred to as “plaintext keys” herein. Because of the value of the encryption keys, the keys themselves often become targets for hackers. Therefore, keys are often encrypted prior to storage or transport to form an encrypted key. The key used to encrypt and decrypt cryptographic keys is referred to as a Key Encryption Key (KEK). Encrypting the plaintext key provides another layer of security since a hacker cannot use the encrypted key without the corresponding key encryption key.
In a typical system, data encryption processing is done either via host cryptographic processing software or an independent cryptographic accelerator. The host system might have a secure key storage area such as a Trusted Platfor Module (TPM) or a Smartcard to protect the plaintext key or KEK. However, when the KEK or plaintext key are being used, they need to be transferred to the host system or the crypto-acceleration hardware. This often leaves a copy of the plaintext key material in unprotected host memory. A very common attack is to search the host memory and find the key material.
An unauthorized user having the plaintext key will be able to decrypt any data encrypted using the plaintext key. This will potentially compromise any sensitive data encrypted using the compromised key. Hence, it is important to protect the key that is used to encrypt or decrypt data, particularly sensitive individual, corporate or government data. Conventional methods to provide a secure key management infrastructure usually have the plaintext keys or both the encrypted keys and the key encryption keys on the host system. However, if the host stores plaintext keys and is vulnerable to an attack, then a hacker can access the plaintext keys to cryptographically process sensitive data. Also, if the host stores both the encrypted key and the associated key encryption key then a hacker can use the key encryption key to decrypt the encrypted key and generate a plaintext key to cryptographically process sensitive data. Accordingly, a secure key management system and method are required to overcome these deficiencies.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers may indicate identical or functionally similar elements.